# import sys
# sys.setrecursionlimit(100000)   #  设置递归的深度

def sum_numbers(num):
    print(num)
    # 递归的出口很重要， 否则会出现死循环
    if num == 1:
        return
    sum_numbers(num - 1)


def func(n):
    if n == 1:
        return 1
    return n + func(n - 1)


def steps(n):
    if n == 1 or n == 2:
        return 1
    return steps(n-1) + steps(n-2)

if __name__ == '__main__':
    sum_numbers(3)
    print('-' * 50)
    print(func(3))
    print('-' * 50)
    print(steps(6))

